Exteding Form Core Component

@Override
public List<com.adobe.cq.wcm.core.components.models.form.OptionItem> getItems() {
    return items;
}

package com.abc.core.models;

import java.util.List;

import com.adobe.cq.wcm.core.components.models.form.OptionItem;
import com.adobe.cq.wcm.core.components.models.form.Options;

public interface FormRadio extends Options {

    String getTitle();

    List<OptionItem> getItems();

}

package com.abc.core.models;

import com.adobe.cq.export.json.ComponentExporter;
import com.adobe.cq.export.json.ExporterConstants;
import com.adobe.cq.wcm.core.components.models.form.OptionItem;
import com.adobe.cq.wcm.core.components.models.form.Options;
import com.adobe.cq.wcm.core.components.util.AbstractComponentImpl;
import lombok.experimental.Delegate;
import org.apache.sling.api.SlingHttpServletRequest;
import org.apache.sling.models.annotations.*;
import org.apache.sling.models.annotations.injectorspecific.ChildResource;
import org.apache.sling.models.annotations.injectorspecific.Self;
import org.apache.sling.models.annotations.injectorspecific.ValueMapValue;
import org.apache.sling.models.annotations.via.ResourceSuperType;

import javax.annotation.PostConstruct;
import javax.inject.Inject;
import java.util.List;

@Model(adaptables = SlingHttpServletRequest.class, adapters = { FormRadio.class,
        ComponentExporter.class }, resourceType = FormRadioImpl.RESOURCE_TYPE, defaultInjectionStrategy = DefaultInjectionStrategy.OPTIONAL)
@Exporter(name = ExporterConstants.SLING_MODEL_EXPORTER_NAME, extensions = ExporterConstants.SLING_MODEL_EXTENSION)

public class FormRadioImpl extends AbstractComponentImpl implements FormRadio {

    public static final String RESOURCE_TYPE = "pmi-atomsmolecules/components/core/form/radio";

    @Self
    @Via(type = ResourceSuperType.class)
    @Delegate(excludes = DelegationExclusion.class)

    private Options options;

    @PostConstruct
    public void init() {
        this.options = resource.adaptTo(Options.class);
    }

    @ValueMapValue
    private String title;

    @ChildResource
    private List<OptionItem> items;

    @ValueMapValue
    @Default(booleanValues = false)
    private boolean textIsRich;

    public boolean isRichText() {
        return textIsRich;
    }

    @Inject
    public FormRadioImpl(SlingHttpServletRequest request) {
        this.options = request.adaptTo(Options.class);
    }

    public Object getFormId() {
        return FormUtil.getInheritedFormId(resource);
        //return null;
    }

    @Override
    public String getExportedType() {
        return FormRadioImpl.RESOURCE_TYPE;
    }

    @Override
    public String getTitle() {
        return title != null ? title : options.getTitle();
    }


    @Override
    public List<OptionItem> getItems() {
        return items;
    }

    private interface DelegationExclusion {
        String getExportedType();
        String getTitle();
    }

}

Thanks